Post Natal Adipose Tissue and Bone Growth

Question 1

Sex/age effect on Marbling

Answer 1

LEAST FAT TO MOST FAT IN SAME SPECIES
Beef: bulls, steers, heifer
Sheep: Rams, whether, Ewes
Pork: Boars, gilts, Barrows

Question 2

Breed effect on Marbling

Answer 2

British breeds > continental breeds or angus, Hereford, shorthorn > Charolais, Limousin, simmental

Question 3

Adipose depots and market value

Answer 3

Visceral fat
Inter-muscular fat
subcutaneous fat - back fat - waste fat (Acetate which is increased by fiber fermentation in the rumen, is the main energy source for back fat)
Intra-muscular (perimysial) fat - taste fat (glucose and or propionate are the main energy sources for marbling in beef; triglycerides are predominant in marbling but in very lean meat, the cell wall phospholipids, which are associate with protein as lipoprotein may account for up to one third of fat content)
Bone marrow - ribs sternum, vertebra and medullary canal of long bones

Question 4

Fat Saturation

Answer 4

the higher the concentration of SFA, the harder the fat (Lamb > beef > pig > chicken)

pigs have a higher concentration of unsaturated fatty acids in their fat when compared with lambs and cattle (chicken > pig > beef > lamb)

Lamb has more branched chain fatty acids (MOA) and 4-methyl-nonanoic acids (MNA) are the main determinants of mutton odor

Question 5

Melting temperature

Answer 5

Saturated > Unsaturated

Question 6

Meat firmness

Answer 6

Saturated > Unsaturated

as the animal grows, the proportion of fatty acids change to more SFA, resulting in a harder tissue in the carcass

Question 7

The fatty acids composition in meat and stability for quality traits

Answer 7

the fatty acids composition in the fat depots determines the firmness or hardness of carcass fat
Lambs have the hardest fat, cattle rank second, and pigs have much softer fat than lambs or cattle
The higher the concentration of saturated fatty acids, the harder the fat
When retail cuts are frozen and held in a freezer for several months the harder the fat (higher concentration of SFA) the grater the stability for quality traits and reduced rancidity development

Question 8

Conjugated Linoleic Acid (CLA)

Answer 8

Anti-carcinogenic, anti-obesity, anti-diabetic
Intermediate in conversion of linoleic acid to stearic acid in rumen
Grass fed beef provides a higher concentration of vaccenic acid doe synthesis of CLA
Desaturation of vaccenic acid synthesis CLA
Beef contains about 1.7-108 mg CLA/g fat

Question 9

Low nutritional plane in pigs

Answer 9

increases adipocyte water
increases saturation of fatty acids
Boar more unsaturated fatty acids than castrates
reduce adipocyte size

Question 10

Diet and Fat saturation in beef

Answer 10

beef from cattle fed corn diet has increase in oleic acid
beef from pasture fed cattle slightly more saturated and CLA
beef from cattle fed grain tends to me mostly saturated
nutritionally restricted or lean animals tend to have saturated fatty acids

Question 11

Diet effect on intra-muscular fat deposition: during finishing period

Answer 11

intramuscular adipose tissue grows by hyperplasia
subcutaneous by hypertrophy

Question 12

Factors affecting Bone growth

Answer 12

Genetics
Environmental factors: gravitational and mechanical stress
Exogenous or dietary factors: Nutrition
Endogenous factors: mostly hormones (growth hormones, thyroid hormones, estrogen, and testosterone)
sex in animals (through testosterone and estrogen)

Question 13

Sex hormones and bone growth

Answer 13

Estrogen
increases long bone growth initially
inhibits bone resorption
increases calcium

Testosterone
increases long bone growth initially
increases bone density

both at high concentrations encourage calcification of epiphyseal cartilage
reduce stature